Earth boring bit



Aug. 9, 1938. c. E. REED EARTH BORING BIT Filed Nov. 27, 1936 II H HIHH' i: i 5 15 5a Patented Aug. 9, 1938 2,126,035

UNITED STATES PATENT orno:

imam some BIT Clarence E. Reed, Wichita, Kans.,-assignor to, Chicagolneumatic Tool Company,-New York, N. Y., a corporation of New Jersey Application November 27, 1936, Serial No. 113,071 20 Claims. (01. 255-71) The invention is an improvement upon the gen- In this invention frusto-conical roller bearings eral form of earth boring bits employing. frustoare employed with their larger ends positioned conical anti-friction roller bearings. towards the axis of the drill and tapering towards The invention consists in the features and conithe outer side of the drill. The bearing is thus bination and arrangement of parts disclosed increased in size and the thrusts tending to push r herein and particularly pointed out in the apthe top portion of the cutter towards the drill pended claims. y axis are sustained by these. tapered roller bearings,

In the drawing, Fig. 1 is a central vertical sec-, which also serve to rotatively lock the cutter on tional view of thecutter with the spindle, supthe spindle.

.1 port and roller bearing organization shown partly It will be noted that the spindle and support In side elevation. are integral, the cutter is in one piece and that Referring to the drawing, the roller cutter l is all raceways are smooth, unbroken, uninterrupted of frusto-conical form, having a toothed base surfaces throughout their extent. The cutter encutting zone la and a toothed frusto-conical closes the end of the spindle and presents a '1 apex cutting zone lb. The invention is not diflicult problem of assembly solved by the limited to afrusto-conicalcutter form. Cylindriarrangement of the parts of this invention. cal cutter form may be employed. As shown in the drawing, the spindle is inte- The two zones of the frusto-conical form of grally formed with its base or support, which cutter are at an inclination to each other. The has a shank extending upwardly to fit into a teeth of the base zone are comparatively wide and recess in the bit head, not shown, wherein it is 20 action possible to obtainin any given cutter. and anti-friction members above described. That diameter 11118130700111.6811 cutter than has hereto-. fined by two intersecting ce each of which extend in planes radial from the axis of the suitably secured, as, for instance, by welding.

cutter. The teeth of the frusto-conical apex zone The spindle has a cylindrical raceway surface are arranged in widely spaced apart circum-- 2a. thereon, also a frusto-conical raceway surface ferential rows. The cutter is in one piece. 3a and another cylindrical raceway surface 4a,

25 It is well known in the art that a cylindrical a thrust shoulderGa and a flange I. The thrust cutter form rolling in a circular path on the botshoulder 6a forms a friction bearing surface contom of the bore hole has a non-true rolling action tacting a friction bearing surface of the cutter. resulting in the so-called twisting or scraping The flange 1 retains the rollers 4 in position. a tio v on the formation at the bottom of the Cylindricalanti-friction rollers 2 are mounted 30 hole. A frusto-conical cutter form having a base on the raceway a, cylindrical rollers 4 are mount- 90 cutting Zone inc ined to a frusto-conical apex ed on the raceway 4a, and frusto-conical rollers cutting zone has similar twisting action of the 3 are positioned on thereweway cutter teeth, but modified in extent. The inclina The fr toon l tt r has a bore conformtion of the cutter axis, also modifies the cutting ins n r l y to the configuration of h sp ndl In this invention, using a frusto-conical c tte is to say, it has a bore with raceway surfaces comform as shown in Fig. 1, the cutter axis is set at n m ta to the way surfa es on the an inclination of thirty (30) degrees, as indicated p for instance, for a c on roller on the drawing, which enables the use of a larger bearings 2 a n it has a groove whol y d fore been used in frusto-conlcal cutter bits of this Surfaces is inclined to the cutter exis- One of type. This setting of the axis of th tt i t these intersecting surfaces is the raceway surface sifles certain-thrusts imposed upon the cutter in thQfruSW-C0ni0a1 roller bearings a operation. The cutter teeth have greater difierthe other of these intersecting surfaces is that 5 ential of speed of travel, therefore of contact with marked 1/ djac nt the larger end face of the the surface of bottom of hole in the differ nt rows frusto-conical roller bearings 3. The bore of the of teeth, and much greater and more rapid discutter also has a thrust frictional bearing surintegration of the bottom of the bore hole results. face. The cutter has a bore hole 5, closed by a. The thrusts have beenvery severe on the bearplug 5a. This bore hole is at an inclination to ings, particularly the end portion of the bearing the axis of the spindle and registers with the 5 towards the drill axis. The drill axis is indicated frusto-conical space between the spindle and the on the drawing by the line m-x. The usual form cutter frusto-conical raceway surfaces. The of bearing breaks down much too soon for efilcifrusto-conical roller bearings are inserted through ent and sustained maintenance of the cutting this hole to their operating position, after which capacity of the teeth. v the hole is plugged. The plug 5a. serves only to 5 close the open hole, and has no other operating function, than to keep earth from entering. After the tapered rollers are inserted to their operating position between the frusto-conical raceway surfaces on the cutter and on the spindle, theinterrelation of all parts is such that the cutter cannot come oi! the spindle because of compression of the tapered rollers through their peripheries contacting cutter and spindle. Holes through cutter shells have been used in this industry for inserting balls and rollers, but they are heretofore used in such manner that the operating loads imposed on the cutter had to be sustained in whole or in part by the plug which would loosen because it formed a part of the raceway. In this invention the position of the hole and the angle of its inangle of inclination of the cutter axis.

clination to the raceway is such that the operating thrusts on the tapered roller bearings cannot be transmitted to the plug.-

In assembling the organization, the cylindrical rollers are placed on their respective raceway surfaces and the cutter is positioned on the spindle and cylindrical rollers. The tapered rollers 3 are then inserted one at a time through the hole 5 and after all are in place, the plug 50. is inserted in the hole; The plug may bescrew threaded, or welded, or both, to retain it.

It is of course well known that in the usual frusto-conical roller cutters there is a well defined end thrust of the cutter towards the support. Such end thrust varies directly with the In this invention and in combination with the assembly and the arrangement of the parts, the angle of inclination has been reduced from the usual 38 to 42.5 degrees to approximately 30 degrees, and this position of the frusto-conical cutter is so much more nearly approaching the vertical, that the thrusts of operation which tend to rotate the body of the cutter by pushing inwardly or outwardly axially are so much modified from the heretofore usual conditions that the general average conditions result in the end thrusts being largely reversed in direction. That is .to say, the destructive, predominating end thrusts of the operations as they aifect the body of the cutter tend to push it towards the axis of the drill to such extent that the end thrust bearing should be reversed from the usual practice. Therefore, inthis invention, the, main rolling,end thrust bearing of the structure is positioned to sustain end thrust of the cutter towards the drill axis, and the and thrust of the .cutter that may occur towards the. support outwardly from the drill axis, is sustained by the spindle. Sufficient clearance is allowed at the ends of the rollers 2 so that the rollers will not be in compression endwise;

the rollers 4 are relieved by the space and the flange I, and the tapered rollers are relieved endwise so that all operating loads thereon are sustained by the periphery of the tapered rollers. The shoulder 6 also prevents any endwise compression of the tapered rollers. It is to be understood that, the tapered rollers sustain radial thrusts in addition to end thrusts of the cutter;

1. A rollercutter and roller bearing assembly for an earth boring drill comprising a cutter having its axis inclined approximately thirty degrees to a horizontal, a spindle, and tapered roller bearings positioned between the cutter and the spindle with their larger ends towardscthe axis of the drill. a

2. A roller cutter and roller'bearing assembly for an earth boring drill comprising a roller cutter, a spindle, a support, roller bearings adjacent the support and between the cutter and the a set of tapered roller bearings positioned be-.

tween the sets of rolling bearings with the larger ends of said tapered roller bearings towards the axis of the drill. I

.4. A roller cutter and roller bearing assembly for an earthboring drill comprising a roller cutter, a spindle, a support, tapered roller bearings positioned with their larger ends towards the axis of the drill, and other rolling bearings between the cutter and the spindle.

5. A spindle support and spindle for an earth boring drill comprising a spindle bodyv portion having thereon a frustoconical raceway surface for roller bearings tapering towards the support, the spindle havinga free end.

6. As an article of manufacture, a spindle support and spindle for an' earth boring drill said spindle having thereon vafrusto-conical raceway surface for roller bearings tapering towards the support, another raceway on said spindle and a thrust sustaining bearing surface.

'7. A roller cutter for an earth boring drill comprising a toothed exterior and a bore having a plurality of raceway bearing surfaces, said bore being closed at one end, and a groove in said bore wholly defined by two intersecting surfaces, each of which surfaces is inclined to the'cutter axis, in combination with a shouldered spindle and frusto-conical anti-friction rollers, one end face of which bears only on one ofthe intersecting.

surfaces and the other end face of which bears only on the shoulder on the spindle, the other of 'said intersecting surfaces ofthe roller cutter servspaced apart circumferential rows, the axis of the,

cutter being arranged for positioning inclined to the axis of 'the drill, said cutter having a plurality of roller bearing raceway surfaces in its bore and a groove for retaining means, said groove being formed by two intersecting surfaces,

each of'which surfaces is inclined to the cutter axis, said retaining means consisting of frustoconical members rolling on oneof said intersecting surfaces.

9. As an article of manufacture, a spindle support and spindle for an earth boring drill, said spindle comprising a body portion having thereon a frusto-conical raceway surface tapering towards the support, a roller cutter, and tapered roller bearings positioned on said raceway surface and between said spindle and said cutter, the smaller ends of .said tapered roller bearings being directed towards the said spindle support.

10. An article of manufacture according to claim 9 and other roiling bearings between the cutter and the spindle.

ll. A rotary earth boring drill comprising a spindle, a toothed non-true rolling cutter turning about said spindle, having a pronounced end thrust inwardly towards the vertical axis of the drill, and frusto-conical anti-friction rollers between the roller cutter and the spindle having their larger diameter ends inwardly towards the vertical axis of the drill, taking said inward end thrust through a complementary raceway in the cutter and imposing the same upon a complementary frusto-conical raceway on the spindle.

12. A rotary earth boring drill according to claim 11 in which the spindle is arranged with its axis at a comparatively low angle to the horizontal.

13. A rotary earth boring drill according to claim 11 in which the cutter has a toothed base zone at an angle to a toothed conical apex portion, substantially as described.

14. In an earth boring drill, a roller cutter of substantially frusto-conical shape having an interior bore closed at one end and having an interior bearing surface of frusto-conical shape tapering toward the open end of the cutter for cooperation with frusto-conical roller bearings.

15. A roller cutter mounting comprising a spindle, a roller cutter enclosing said spindle, frustoconical roller bearings between said spindle and cutter, said cutter having an opening for the insertion of said roller bearingsgsaid opening extending along the axis of one of said roller bearings.

16. A roller cutter mounting comprising a spindle located to one side of the vertical axis of thedrill, a support at one end of the spindle, a one piece roller cutter encloslngsaid spindle and located to one side of the vertical axis of the drill,

bearings and the support, said roller bearings and rolling bearings having between them a portion of the wall of the cutter.

17. In a roller cutter organization for an earth boring apparatus, a roller cutter, a frusto-conical roller bearing positioned with the larger ends of the frusto-conical rollers towards the axis of the apparatus and a spindle having a frusto-conical surface on which said rollers bear, the larger diameter part of said surface being nearer to said axis than the smaller diameter part of said surface for sustaining end thrusts of the cutter inwardly of the apparatus.

18. In a roller cutter organization for earth boring apparatus, a spindle, a toothed roller cutter and anti-friction roller bearings between the spindle and the cutter comprising a set of rollers taking radial loads, and a set of frusto-conical rollers arranged with their larger diameter ends towards the vertical axis about which the apparatus rotates taking end thrust of the cutte inwardly towards said vertical axis.

19. A roller cutter for an earth boring drill comprising a toothed exterior. and a bore closed,

at one end and open at the other, and having a plurality of bearing surfaces, one of said surfaces being a cylindrical raceway bearing surface and another of said surfaces being a tapered raceway bearing surface with the smallerlend of said tapered surface towards the open end of the bore.

20. A roller cutter for an earth boring drill comprising a toothed exterior and a bore closed at one end and open at the other, and having a plurality of bearing surfaces, one of said surfaces being a tapered raceway bearing surface for frusto-conical roller bearings with the smaller end of said tapered surface towards the open end of said bore, and said tapered surface positioned in said bore between two other roller bearing raceway surfaces.

CLARENCE E. REED. 

